Hacker News Reader

There are other options, i.e. opt-in vs opt-out, separate sections (only show in sidebar), instant on/off, and overall greater transparency.

Surfing in anonymous mode with Chrome should work as an opt-out, or shouldn't it?

only as long as you don't log in to google or anything else before you search.

There's obvious opt-out things for the miniscule amount of people who care.

Exactly the same as the "search term leakage" rubbish.